Reactively loaded broadband antenna for use in the 10 through 160 meter bands



G. A. PARTRIDGE 3,274,600 REACTIVELY LOADED BROADBAND ANTENNA FOR USE IN THE 10 THROUGH 160 METER BANDS Sept. 20, 1956 Filed Feb. 14, 1963 FIG.2

United States Patent Office 3,274,600- Patented Sept. 20, 1966 REACTIVELY LOADED BROADBAND ANTENNA FOR USE IN THE THROUGH 160 METER BANDS George Alfred Partridge, 17 Ethel Road, Broadstairs, England Filed Feb. 14, 1963, Ser. No. 258,592 6 Claims. (Cl. 343-749) The invention relates to aerial arrangements.

It is often required in high frequency radio communication systems, to have transmitting and receiving aerial arrangements which are of high radiation efficiency, and extensive frequency coverage, but nevertheless occupying only a small space and of low weight. This is particularly so in domestic or mobile installations, whether on land, at sea, in the air, or in outer space.

This invention seeks to provide an aerial system which takes up only a small space and which, preferably, but not essentially, can be easily dismantled for transportation, and which can effectively cover a wide range of frequencies for both transmitting and receiving purposes within a broad radio spectrum.

According to the invention there is provided a radio frequency aerial comprising an inductor having an inductance of substantially from 35 to 43 microhenries, a pair of metal arms one end of each of which is connected to a different end of a coil of said inductor, said metal arms extending outwardly in opposite directions in line along the axis of the inductor, and a wire feeder of variable length connected to said aerial.

Preferably, each of said metal arms is readily attachable to and detachable from the corresponding end of said inductor, and said wire feeder is readily attachable to and detachable from said aerial.

Conveniently, said inductor has an elongated former possessing suitable insulating properties and round the former is arranged a helical coil having a variable number of turns of wire to give an inductance of substantially 35 to 43 microhenries.

In the prefer-red form of the invention described hereinafter said metal arms are hollow metal tubular members. Alternatively, said metal arms may consist of a thin outer skin of metal supported on a central cylinder of insulating material.

Preferably, one of said metal arms is longer than the other and for the 10, 15, 20, 40-, 80 and 160' meter bands very satisfactory results have been achieved with the wire feeder connected to the other (outer) end of the longest metal arm. However, suitable tapping points may be provided over the combined length of the coil and longer metal arm, preferably on the coil, for connection of the wire feeder for improved results on the 10 to 40 meter hands. If desired, the length of the wire feeder can be chosen to achieve aerial resonance.

One preferred form of the invention is described hereinafter by way of example only, reference being made to the accompanying drawing, in which:

FIGURE 1 is a side view of an aerial according to the invention, and

FIGURE 2 is a section of the aerial proper (i.e., without wire feeder) taken on the line of AA of FIG- URE 1.

Referring .to the drawing, the aerial comprises an elongated inductor in the form of an elongated or rod-like former 1 having a wire conductor 2 wound thereon to form a simple single-layer helical coil. The said rodlike former 1 may be of hardwood as described hereinafter, or it may be fabricated of any other well known suitable electrical insulator material which is substantially non-inductive of radio frequency waves. Two tubular metal arms 3 and 4 of unequal length (in the drawing 4 is the longer) each have one end (the inner end) attached to a different end of the former 1 by means of a tight push fit. The metal arms 3 and 4 are secured in {position on the former and each end of the coil 2 is connected to the corresponding metal arm by means of wing nuts and bolts 6a and 6b. By virtue of this construction each of said metal arms is readily attachable to and detachable from the corresponding end of said inductor. An insulated wire feeder 5 is readily attachable to and detachable from the other (outer) end of the longer metal arm 4 by means of a further wing nut and bolt 60.

It has been found that one of a number of arrangements for the inductor, providing the necessary inductance, consist of 200 turns of No. -16 British standard wire gauge enamelled high conductivity copper wire close wound on a former of %-lIlCl'l diameter hardwood of total length substantially 20 inches.

The metal arms 3 and 4 should be preferably hollow as stated for maximum rigidity and minimum weight. Copper tubing of 4-inch internal diameter and extending for a distance of 2 feet 8 inches, and 3 feet 8 inches respectively either side of the inductor has been found to be satisfactory in practice. The choice of 2 feet 8 inches and 3 feet 8 inches respectively for the two metal arms 3 and 4, whereby one arm is approximately two thirds of the length of the other arm, has been determined empirically, and the use of these dimensions has been found to result in amazingly high radiation efficiency over a very wide range of frequencies, particularly when the aerial is used at ground level, and when it is fed with the recommended 8-fo0t length (see below) of insulated wire feeder. The insulated wire feeder may be of single or multistrand construction, the length of which may be varied as convenient, and according to the particular frequency at which the aerial is required to be tuned. It has been found in practice that a length of 8 feet is particularly suitable for the 1.8, 3.5, 7.0, 14.0, 211.0 and 28.0 megacycle radio amateur frequency bands.

Good results are obtained on the above frequency bands if the aforementioned 8-foot wire feeder is always attached to the other or outer end of the longer metal arm. However, a plurality of tapping points may be provided over the combined length of the coil 2 and longer metal arm 4. For the 10, 15, 20 and 40 meter bands such tapping points are located approximately and respectively at the points 7a, 7b, 7c and 7d in FIGURE 1, the wire feeder being connected as shown for the and meter band.

Referring to FIGURE 2, if the ends of the former 1 are extended for the length of the arms 3 and 4, the metal tubing of the arms may be replaced by a thin skin of metal coated or wrapped around the ends of the former.

While there have been described above what are presently believed to be the preferred forms of the invention, variations thereof will be obvious to those skilled in the art and all such changes and variations which fall within the spirit of the invention are intended to be covered by the generic terms in the appended claims, which are variably worded to that end.

What is claimed is:

l. A broadband transmitting and receiving radio aerial having high etficiency over the 10 through 160 meter bands without the need of electrical or mechanical adjustment to the aerial, comprising an inductance coil wound on an elongated former of insulating material, said coil having a fixed inductance of substantially 35 to 43 microhenries, a first elongated radiating member positioned on one end of said former and colinear therewith, a second elongated radiating member positioned on the other end of said former and colinear therewith, the

length of said first radiating member being substantially 3 feet 8 inches and the length of said second radiating member being substantially 2 feet 8 inches, means forming an electrical connection between each end of said coil and the adjacent end of the corresponding radiating member, and means for connecting a feeder to said first radiating member at a position adjacent the end of said first radiating member remote from said coil.

2. The aerial claimed in claim 1, wherein each radiating member is readily attachable to and detachable from the corresponding end of said elongated former.

3. The aerial of claim 2, in which each said radiating member is in the form of a hollow metal tube.

4. The aerial of claim 3, in which each said metal tube makes connection with the corresponding end of said elongated former by means of a tight push fit thereon.

5. The aerial of claim 1 wherein said first and second radiating members comprise spaced metallic coatings on spaced oppositely extending portions of said elongated insulating coil former.

6. The aerial of claim 1, in which said first radiating member comprises a metal tube slipped onto one end of said former, said second radiating member comprising a metal tube slipped onto the other end of said former, and releasable locking means for holding each of said tubes in place on the corresponding ends of said former.

References Cited by the Examiner UNITED STATES PATENTS 2,771,604 11/1956 Goldstein -3. 343-749 2,841,789 7/1958 Bassett 343-749 2,881,428 4/1959 Batchelor 343-750 FOREIGN PATENTS 69,462 7/ 1945 Norway.

HERMAN KARL SAALBACH, Primary Examiner. W. K. TAYLOR, P. L. GENSLER, Examiners. 

1. A BROADBAND TRANSMITTING AND RECEIVING RADIO AERIAL HAVING HIGH EFFICIENCY OVER THE 10 THROUGH 160 METER BANDS WITHOUT THE NEED OF ELECTRICAL OR MECHANICAL ADJUSTMENT TO THE AERIAL, COMPRISING AN INDUCTANCE COIL WOUND ON AN ELONGATED FORMER OF INSULATING MATERIAL, SAID COIL HAVING A FIXED INDUCTANCE OF SUBSTANTIALLY 35 TO 43 MICROHENRIES, A FIRST ELONGATED RADIATING MEMBER POSITIONED ON ONE END OF SAID FORMER AND COLINEAR THEREWITH, A SECOND ELONGATED RADIATING MEMBER POSITIONED ON THE OTHER END OF SAID FORMER AND COLINEAR THEREWITH, THE LENGTH OF SAID FIRST RADIATING MEMBER BEING SUBSTANTIALLY 3 FEET 8 INCHES AND THE LENGTH OF SAID SECOND RADIATING MEMBER BEING SUBSTANTIALLY 2 FEET 8 INCHES, MEANS FORMING AN ELECTRICAL CONNECTION BETWEEN EACH END OF SAID COIL AND THE ADJACENT END OF THE CORRESPONDING RADIATING MEMBER, AND MEANS FOR CONNECTING A FEEDER TO SAID FIRST RADIATING MEMBER AT A POSITION ADJACENT THE END OF SAID FIRST RADIATING MEMBER REMOTE FROM SAID COIL. 